Connecting structure of exhaust system member and insertion member

ABSTRACT

A connecting structure of an exhaust system member and an insertion member includes a first divided part  44  and a second divided part  45  each formed like a semi-circular cylinder. The first and second divided parts  44  and  45  are coupled like a barrel so that projecting portions  45   c  are engaged with inner sides of bulge portions  44   c,  respectively, and end portions of the first and second divided parts  44  and  45  are contacted to form a circular cross section, the both edge portions of the first and second divided parts  44  and  45  being fixed with each other by welding X 1  to form the exhaust system member (diffuser  43 ). After the insertion member (catalyst carrier case  41 ) is inserted in the end portion  43   a  of the diffuser  43   a,  the end portion and an outer circumferential surface of the catalyst carrier case  41  are fixed by welding X 2  all along the outer circumferential surface.

TECHNICAL FIELD

The present invention relates to a connecting structure of an exhaustsystem member and an insertion member, both of which are used in anexhaust system connected with an engine of a motor vehicle or the likes.

BACKGROUND OF THE INVENTION

Japanese Patent Applications Laid-Open Publication No. 2004-92512 andNo. 09-329019 disclose technology on conventional connecting structuresof an exhaust system member and an insertion member. As shown in FIG. 6,both edge portions of a divided part 011 formed like a semi-circularcylinder is coupled with inner sides of bulge portions 012 a of adivided part 012 formed in a semi-circular cylinder, so that the bulgeportions 012 a are formed to expand in an outward direction to entirelyform a substantially circular cross section. Then the both edge portionsof the divided parts 011 and 012 are fixed with each other by welding toform an exhaust system member 010, and a not-shown insertion member isinserted into an end portion of the exhaust system member 010. Then theend portion of the exhaust system member 010 and an outercircumferential surface of the insertion member are fixed with eachother by welding all around the outer circumferential surface.

DISCLOSURE OF THE INVENTION Problem(s) to be Solved by the Invention

The above-described conventional inventions, however, have problems inthat a gap O, shown in FIG. 6, is generated between the end portion ofthe exhaust system member 010 and the insertion member, so that, in acase where they are welded with each other all along the outercircumferential surface, a lot amount of welding material is needed toclose the gap O, and it takes a relatively long time to weld them.

The present invention is made in order to solve the above-describedproblems, and it is an object thereof is to provide a connectingstructure of an exhaust system member and an insertion member where alot of amount of welding material is not needed and they can be weldedwith each other in a relatively little time in a case where an endportion of the exhaust system member, which is formed by coupling afirst divided part and a second divided part with each other, and anouter circumferential surface of the insertion member are welded witheach other all along the outer circumferential surface.

Means for Solving the Problems

According to a first aspect of the present invention there is provided aconnecting structure of an exhaust system member and an insertionmember, where the exhaust system member includes a first divided partand a second divided part. The first divided part is formed like asemi-circular cylinder to have bulge portions respectively projecting inan outward direction at both edge portions thereof except end portionsthereof; and the second divided part is formed like a semi-circularcylinder to have projecting portions respectively engageable with innersides of the bulge portions of the first divided part at both edgeportions except end portions thereof. The first divided part and thesecond divided part are coupled with each other to form a barrel-likeshape so that the projecting portions are engaged with the inner sidesof the bulge portions, respectively. The end portions of the firstdivided part and the second divided part are contacted with each otherto form a circular cross section, respectively, then the both edgeportions of the first divided part and the second divided part beingwelded with each other. The end portions and an outer circumferentialsurface of the insertion member are welded with each other all along theouter circumferential surface.

EFFECT OF THE INVENTION

In the connecting structure of the exhaust system member and theinsertion member including the first divided part and the second dividedpart. The first divided part is formed like the semi-circular cylinderto have the bulge portions respectively projecting in the outwarddirection at the both edge portions thereof except the end portionsthereof; and the second divided part is formed like the semi-circularcylinder to have the projecting portions respectively engageable withthe inner sides of the bulge portions of the first divided part at theboth edge portions except the end portions thereof. The first dividedpart and the second divided part are coupled with each other to form thebarrel-like shape so that the projecting portions are engaged with theinner sides of the bulge portions, respectively. The end portions of thefirst divided part and the second divided part are contacted with eachother to form the circular cross section, respectively, then the bothedge portions of the first divided part and the second divided partbeing welded with each other. The end portions and the outercircumferential surface of the insertion member are welded with eachother all along the outer circumferential surface. As a result, the endportion of the exhaust system member and the insertion member can havethe circular cross section without a step, thereby no gap being formedtherebetween. Therefore, in a case where the end portions of the exhaustsystem member, including the first divided part and the second dividedpart, and the outer surface of the insertion are joined with each otherall along the outer circumferential surface by the welding, they can bewelded with each other with a relatively little amount of weldingmaterial and in a relatively little time.

BRIEF DESCRIPTION OF THE DRAWINGS

The objects, features and advantages of the present invention willbecome apparent as the description proceeds when taken in conjunctionwith the accompanying drawings, in which:

FIG. 1 is a diagram illustrating an exhaust system that is provided witha connecting structure of an exhaust system member and an insertionmember of a first embodiment according to the present invention;

FIG. 2 is an exploded perspective view showing a diffuser, whichcorresponds to the exhaust system member of the first embodiment;

FIG. 3 is a perspective view showing the diffuser of the firstembodiment;

FIG. 4 is a view showing fixation between the diffuser of a catalyticconverter and a catalyst carrier case of the first embodiment;

FIG. 5 is a view showing the fixation between the diffuser of thecatalytic converter and the catalyst carrier case of the firstembodiment; and

FIG. 6 is a view showing a conventional connecting structure of anexhaust system member and an insertion member.

DESCRIPTION OF REFERENCE NUMBERS

X1, X2 welding

1 engine

2 exhaust manifold

3, 5, 8 flange

4 catalytic converter

6, 9 connecting pipe

7 sub-muffle

10 main muffler

41 catalyst carrier case

41 a catalyst carrier

42, 43 diffuser

43 a end portion (of the diffuser)

44 first divided part

44 a, 44 b end portion (of the first divided part)

44 c bulge portion

45 second divided part

45 a, 45 b end portion (of the second divided part)

45 c bulge portion

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, an embodiment according to the present invention will bedescribed with reference to the accompanying drawings.

First Embodiment

Hereinafter, a first embodiment will be described.

Incidentally, a case will be described, in which an exhaust systemmember is a diffuser of a catalytic converter and an insertion member isa catalyst carrier case that contains a catalyst carrier.

FIG. 1 is a diagram illustrating an exhaust system that is provided witha connecting structure of the exhaust system member and the insertionmember of the first embodiment, FIG. 2 is an exploded perspective viewshowing the diffuser of the first embodiment, FIG. 3 is a perspectiveview showing the same, and FIGS. 4 and 5 are views illustrating fixationbetween the diffuser of the catalytic converter and the catalystconverter carrier of the first embodiment.

First, an entire construction of the first embodiment will be described.As shown in FIG. 1, in an exhaust system that is provided with aconnecting structure of an exhaust system member and an insertion memberof the fist embodiment, the system includes an engine 1, a catalyticconverter 4 that is connected with the engine 1 through an exhaustmanifold 2 and a flange 3, a sub-muffler 7 that is connected with thecatalytic converter 4 through a flange 5 and a connecting pipe 6, and amain muffler 10 that is connected with the sub-muffler 7 through aflange 8 and a connecting pipe 9.

The catalytic converter 4 is composed of a catalyst carrier case 41 thatis made of metal material to be formed like a cylinder, and diffusers 42and 43 that are made of metal material to be formed like a funnel, thediffusers 44 and 45 being connected with both end portions of thecatalyst carrier case 41. The catalyst carrier case 41 corresponds to aninsertion member of the present invention, and each of the diffusers 42and 43 corresponds to an exhaust system member of the present invention.

Further, a catalyst carrier 51 a, shown in FIG. 4, is contained in thecatalyst carrier case 41. The catalyst carrier 41 a employs a metalcatalyst carrier that is formed like a circular cylinder formed by ametal corrugated plate and a metal flat plate, which are not shown,being multiply rolled together with each other, or a ceramic catalystcarrier that is made of porous ceramic material and formed like acircular cylinder. It carries catalyst components such as platinum (Pt)on surfaces of exhaust passages that are formed to penetrate thecatalyst carrier in a longitudinal direction thereof. The catalystcomponents convert harmful components such as nitroxide (NOx) and carbonmonoxide (CO) that are contained in exhaust gas flowing through thecatalyst carrier case 41 into unharmful components to be discharged ascarbon dioxide (CO₂), water (H₂O) and others, by catalysis thereof.Incidentally, in a case of using the metal catalyst carrier, thecatalyst carrier case 41 is fixed by brazing to the catalyst carrier 41a where a corrugated plate and a flat plate are fixed with each other bydiffusion bonding in the catalyst carrier case 41. In a case of usingthe ceramic catalyst carrier, the catalyst carrier 41 a is press-fittedinto and fixed to the catalyst carrier case 41 through a mat.

Hereinafter, connecting structures between the catalyst carrier case 41and the diffuser 42 and between the catalyst carrier case 41 and thediffuser 43 are similar to each other, and accordingly only theconnecting structure of the catalyst carrier case 41 and the diffuser 43will be described in detail.

As shown in FIG. 2, the diffuser 43 is composed of a first divided part44 and a second divided part 45, where the first divided part 44 isformed like a semi-circular cylinder to have bulge portions 44 c thatexpand in an outward direction at both edge portions thereof except bothend portions 44 a and 44 b thereof, and the second divided part 45 isformed like a semi-circular cylinder to have projecting portion 44 cthat are capable of engaging with inner sides of the corresponding bulgeportions 44 c of the first divided part 44 except both end portions 45 aand 45 b thereof.

As shown in FIG. 3, the first divided part 44 and the second dividedpart 45 are coupled with each other like a barrel to entirely have acircular cross section by the projecting portions 45 c of the seconddivided part 45 being engaged with the inner sides of the correspondingbulge portions 44 c of the first divided part 44 and also the both endportions of the first and second divided portions 44 and 45 beingcontacted with each other. Then, the both edge portions of the first andsecond divided parts 44 and 45 are fixed to each other by welding X1,which are indicated by a thick line, to form the diffuser 43.

In this welding process, the welding X1 can be performed along astraight-like welding line to fix the both edge portions of the firstand second divided parts 44 and 45, and therefore good weldabilitythereof can be obtained.

Next, as shown in FIG. 4, the catalyst carrier case 41 is inserted apredetermined depth into an exhaust gas upstream side end portion 43 aof the diffuser 43, and then, as shown in FIG. 5, the exhaust gasupstream side end portion 43 a and an outer circumferential surface ofthe end portion of the catalyst carrier case 41 are fixed with eachother by welding X2 all along the end portion, so that the diffuser 43and the catalyst carrier case 41 are joined with each other.

Herein, in the above-described conventional inventions, the bulgeportions and the projecting portions are formed to extend up to the bothend portions of the diffuser. As a result, gaps are formed between theend portion of the diffuser and the insertion member, which requires alot of welding material to close the gaps. In addition, this closingwork takes a relatively long time.

On the contrary, in the first embodiment, as described above, the bothend portions of the first and second divided parts 44 and 45 arecontacted with each other to entirely form the circular cross section,so that no gap is formed between the exhaust gas upstream side endportion of the diffuser 43 and the catalyst carrier case 41. Therefore,it prevents sputter of the welding from coming in the diffuser 43. Inaddition, the first and second divided parts 44 and 45 are welded witheach other with a little amount of the welding X2 and in a relativelyshort time.

Further, in a state where an exhaust gas downstream side end portion 43b of the diffuser 43 is provided with a flange 5 at its outer side, aperipheral portion of a through hole formed in the flange 5 is fixed toan outer circumferential surface of the diffuser 43 by not-shown weldingall along them.

Incidentally, the catalyst carrier case 41 and the diffuser 42, and thediffuser 42 and the flange 3 are joined with each other similarly to theabove-described joining.

Next, the effects of the first embodiment will be described.

As explained above, the connecting structure of the exhaust systemmember and the insertion member of the first embodiment includes firstdivided part 44 that is formed like the semi-circular cylinder to havethe bulge portions 44 c respectively projecting in the outward directionat the both edge portions thereof except end portions 44 a and 44 bthereof; and the second divided part 45 that is formed like thesemi-circular cylinder to have the projecting portions 45 c respectivelyengageable with the inner sides of the bulge portions 44 c of the firstdivided part 44 at the both edge portions except end portions 45 a and45 b thereof. The first divided part 44 and the second divided part 45are coupled with each other to form the barrel-like lo shape so that theprojecting portions 44 c are engaged with the inner sides of the bulgeportions 44 c, respectively The end portions of the first divided part44 and the second divided part 45 are contacted with each other to formthe circular cross section, and the both edge portions of the firstdivided part 44 and the second divided part 45 are welded with eachother. is The end portions and the outer circumferential surface of thecatalyst carrier case 41 are welded with each other all along the outercircumferential surface. Therefore, in a case where the end portions ofthe diffuser 43, which consists of the first divided part 44 and thesecond divided part 45, and the outer surface of the catalyst carriercase 41 are joined with each other all along the outer circumferentialsurface by the welding X2, they can be welded with each other with therelatively little amount of the welding material and in a relativelylittle time.

While the embodiment has been explained, the present invention is notlimited to the above-described embodiment, and its design changes andmodifications are contained in the present invention as long as they donot depart from the subject matter of the present invention.

For example, the exhaust system member is not limited to the diffuser 43of the catalytic converter 4, and using parts such as ones connectingwith an exhaust pipe can obtain the similar effects.

1. A connecting structure of an exhaust system member and an insertionmember comprising: a first divided part that is formed like asemi-circular cylinder to have bulge portions respectively projecting inan outward direction at both edge portions thereof except end portionsthereof; and a second divided part that is formed like a semi-circularcylinder to have projecting portions respectively engageable with innersides of the bulge portions of the first divided part at both edgeportions except end portions thereof, wherein the first divided part andthe second divided part are coupled with each other to form abarrel-like shape so that the projecting portions are engaged with theinner sides of the bulge portions, respectively; the end portions of thefirst divided part and the second divided part are contacted with eachother to form a circular cross section, wherein the both edge portionsof the first divided part and the second divided part are welded witheach other; and wherein the end portions and an outer circumferentialsurface of the insertion member are welded with each other all along theouter circumferential surface.
 2. The connecting structure of theexhaust system member and the insertion member according to claim 1,wherein the exhaust system member is a diffuser of a catalyticconverter, and wherein the insertion member is a catalyst converter casethat contains a catalyst converter.